Electrode holder for use in electroencephalography



p 1947- G. A. ULETT, JR, ET AL 2,426,958

ELECTRODE HOLDER FOR USE IN ELECTROENCEPHALOGRAPHY Filed Dec. 27, 1944 George A. U/eff, J77 Med fi. O/wwas en El ond my! Patented Sept. 2, 1947 2,426,958 ELECTRODE HOLDER FOR USE IN ELEC- TROENCEPHALO GRAPHY George A. Ulett, .lr., and Fred B. Claussen, Portland, Greg,

War

assignors to America, as represented by the Application December 27,

Claims. (01. l28-2.1')

This invention relates to electroencephalography, and particularly it is directed toward a device for applying and holding electrodes in electrical contact with the scalp for recording electrical potentials of cortical areas.

Since Caton reported electrical activity of the brain in 1874, considerable research and investigation has been conducted in an effort to efficiently utilize this electrical activity in clinical diagnosis of cortical areas. The first investigator to record the electrical potentials from the brain was Berger, who, in 1924, inserted a silver wire into the anesthetized scalp. For several years thereafter he continued his studies and became the first to apply electroencephalography to a clinical diagnostic use. The research in this field has developed several recording instruments that are adequate and satisfactory in operation, some of which are disclosed in Atlas of Electroencephalography" by F. A. and E. L. Gibbs. Considerable advancement likewise has been achieved in the electrode placement since Berger first used the silver wire in the anesthetized scalp. Among the various electrodes and methods of placement contributed to the art, there may be mentioned liquid electrodes and serrated circular metallic electrodes which are held in place by clamps applied to the hair and by adhesive compounds binding the electrodes to the .scalp. The electrode and method of application most commonly used, however, is an electrode paste coated flat solder pellet secured to a copper wire and held to the scalp by collodion, as described by Gibbs. Satisfactory placement of these electrodes requires a high degree of skilled technique acquired only by lengthy practice, and then they consume considerable time in placement. With the widespread use of the electroencephalograph to survey large populations inbo'th military and civilian medicine and with an increased difliculty in obtaining technicians for this work, it has become necessary to devise a fast, simple technique of electrode application. It is this problem of electrode placement that has been confronting electroencephalographers and which issolved by this invention.

The electrode and placement technique associated therewith should be such that the electrode produces no artifacts; is easy to apply, keep on, and remove; and, .it is relatively cheap in production and painless in its application and use. Any metalcapable of establishingelectrical contact with the scalp through a saline solution or paste, such as Sanborn electrode paste, may be the United States of Secretary of 1944, Serial No. 569,936

used for an electrode. The ideal placement of the electrode is such that the independent recordings of the activity from each distinct cortical area may be obtained, unmixed with muscle potentials, movement artifacts or potentials from other cortical areas. Actually, however, the activity immediately under each electrode is so strong in the recording and the activity at slightly distant points are so very weak that only is apparent in the recording. The electrode, therefore, should be adaptable to placement adjustment and be operable with both monopolar and bipolar leads to the recorder.

Accordingly, the method of spring-pressure contact electrode placement of this invention substantially lessens the time required for electrode application; obviates the necessity for long practice in electrode application; dispenses with the use of collodion which is often objectionable to the patient; aids in the comparison of electroencephalographic records from patient to patient by permitting a more uniform electrode placement; and is adjustable and adaptable to monopolar and bipolar leads.

It is therefore an object of this invention to provide a device for supporting electrodes employed in electroencephalography that is adjustable to fit various sizes and shapes of craniums.

It is another object of this invention to provide a device of the class herein described, equipped with adjustable electrodes which are resiliently urged in electrical contact with the scalp of a patient wearing the device.

A further object of this invention is to provide a head gear supporting adjustable electrodes employed in the electroencephalography whereby said electrodes are resiliently held in operative and inoperative positions.

A still further object of this invention is to provide a device of the class herein described which is economical, emcient, and durable.

The foregoing and other objects will be more apparent from reading the specification in conjunction with the drawings forming a part thereof, wherein:

Fig. 1 is a perspective of the head gear with pairs of symmetrical placed electrodes movable over the of the scalp;

Fig. 2 is a cutaway perspective of the electrode supporting and holding assembly pivotally connected with the electrode rotated from normal to show the slanting contact surface;

frontal, parietal and occipital regions spacer I6 having and anterior band 3 are provided with a plurality of longitudinal slots 5 adapted to receive bolts longitudinally movable therein for adjustably mounting electrode supports thereon.

Each of the electrode I5 is a a diameter greater than the width of the slot 5. A nut I1 is threadedly engaged with the bolt I5, thereby rigidly securing the supporting bar II to the head gear at a predetermined position of the band. Pivotally connected to each end of the supporting cross bar I I ciated therewith. A substantially L-shaped spring clip 20 of a suitable electrical conductive material such as bronze, brass and the like, is mounted on and in insulated spaced relationship with the electrode holding bar I9 by a screw 2i surrounded by intermediate the clip and the spring clip 20 and supporting and adapted to receive an electrode I2 which is held therein bya set screw 26 inserted through an aperture 21 provided in the downwardly ex- 2I. The spring action of the clip 20 urges it in the electrode I2.

The single electrode holder and support used on the head band I is similar to the twin mount described above. The difierence between the two mounts being that the single mount does not have a supporting cross bar II but instead has a secured at one end to a stud 3| attached to the cross bar II, or the supporting insulation bar I 3 connected to the supporting bar I I the tensioned coil spring electrode into contact with the The adjustment of the device is relatively simple and easy. The head adjusting the three bands to the required size, and again tightening the aforementioned nuts on the bolts. The various electrode supporting bars of convenient lengths may be adjusted by loosening the nut I1 on each bolt I5 assembly and sliding in an antero-posterior movement in the elongated slots 5 which are adjustably mounted along the sides of the head band I to permit recordings from lateral regions of the head.

The electrode is preferably a brass rod 12 tapered at one end for attaching a cup-shaped solder pellet 3 thereto. The solder pellet is provided with a slanting or arcuate contour 35 adapted to accurately engage the scalp of a patient. The electrode is freely adjustable by releasing the tension of the set screw 26.

In using this device, the electrodes are positioned over the cortical areas and electrode paste applied to the scalp engaging surface of the solder pellet, care being taken that the brass rod, solder pellet and electrode paste do not contact as an artifact would be produced. The hair is then parted, the electrode paste applied to the exposed scalp, and the paste coated electrode pivoted to the operable position.

Recordings are most conveniently taken with the patient in a sitting position. Recording in the supine position is possible with the use of a block pillow placed beneath the neck and base of the occiput of the patient.

This device has been particularly useful in rapidly and easily applying electrodes for electroencephalographic diagnosis and differential diagnosis of epilepsies; location of neoplasms; presence and location of cerebral diseases; diagnosis and differential diagnosis of psychoses; and, qualitative and quantitative studies of emotional states.

Having thus described our invention, what we claim as new and wish to secure by Letters Patent 1. A device for electrode placement in electroencephalographic diagnosis comprising a head gear, electrode supports secured to said head gear, electrode holders pivotally connected to said supports, electrodes fastened to said holders, and spring means connected to said electrode supports and holders, said spring means adapted to actuate said holders about their pivotal connection with said supports for holding said electrodes in operative position during recording and in an inoperative position when not in use.

2. A device for electrode placement in electroencephalographic diagnosis comprising an adjustable head gear, electrode supports adjustably secured to said head gear, electrode holders mounted to said supports and movable in relationship therewith to operative and inoperative positions, and spring means connected to said electrode supports and holders, said spring means adapted to actuate said holders on said supports for selectively holding said electrodes in operative and inoperative positions.

3. A device for electrode placement in electroencephalographic diagnosis comprising an adjustable head band adapted to pass around a patients head, an adjustable center band secured to said head band and adapted to pass over the patients head, longitudinal slots in the aforesaid bands, bolts longitudinally movable in said slots, supporting bars associated with said bolts and movable therewith, means fastening said bars to said bolts and rigidly securing said bars and bolts at predetermined positions in said slots, electrode holders pivotally mounted to said bars, electrodes fastened to said holders, and spring means connected to said bars and electrode holders, said spring means adapted to actuate said holders about their pivotal connection with said bars for selectively holding said, holders in operative and inoperative positions.

4. A device for electrode placement in electroencephalographic diagnosis comprising an adjustable head band adapted to pass around a patients head, an adjustable center band secured to said head band and adapted to pass over the patients head, longitudinal slots in the aforesaid bands, bolts longitudinally movable in said slots, supporting bars associated with said bolts and movable therewith, means fastening said bars to said bolts and rigidly securing said bars and bolts at predetermined positions in said slots, electrode holders pivotally mounted to said bars, electrodes fastened to said holder, and resilient means connecting each said supporting bar and respective holding bar whereby said electrode is selectively held in operative and inoperative positions.

5. A device for electrode placement in electroencephalographic diagnosis comprising an adjustable head gear, electrode supports adjustably secured to said head gear, electrode holders mounted to said supports and movable therewith to assume operative and inoperative positions, electrodes removably secured to said holders, means establishing electrical continuity through said electrodes, and spring means connected to said electrode supports and holders, said spring means adapted to actuate said holders on said supports for selectively holding said electrodes in operative and inoperative positions.

GEORGE A. ULETT, J a. FRED B. CLAUSSEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,684,859 Catlin Sept. 18, 1928 678,417 Muller July 16, 1901 768,721 Bassell Aug. 30, 1904 1,487,998 Woolf Mar. 25, 1924 2,151,458 Allen Mar. 21, 1939 2,325,300 Bisnoff July 27, 1943 

